A multilayer printed circuit board (PCB) is usually consisted of a number of conductor layers used for ground and power planes, and also for forming signal planar interconnect circuits where the conductor layers are isolated by a material. Planar interconnect circuits at signal layers can be developed on the base of planar transmission lines (as for an example, varieties of microstrip lines, strip lines, coplanar lines, and slot lines) which have typically low return and leakage losses that give a possibility to develop high-performance planar circuits.
However, transitions providing connections between different signal layers of the multilayer PCB by means of via structures have usually high enough return and leakage losses that finally make worse the electrical performance of whole interconnect circuits embedded in the multilayer PCB.